Two-temperature refrigerating means



Patented Se t. 20, 1949 TWO-TEMPERATURE REFRIGERATING MEANS Minor Harrison Strang and Ralph J. Burger,

Kendallville, Ind., assignors to McCray Refrig- I erator Company, Kendallville, Ind., a corporation of Indiana Application February 16, 1948, Serial No. 8,515

6 Claims.

different compartments preferably but not neces- I sarily in a unit type refrigerator.

The primary object of the invention is the provision of a new and useful refrigerating means of this character wherein primary and secondary refrigerating circuits are provided in different compartments to maintain them at different predetermined temperatures in a simple, efiicient, accurately controlled and economical manner.

Another object of the invention is the provision in a refrigerating system of the character described of primary and secondary refrigerating circuits associated with different compartments, with the cold imparting temperature of the refrigerant in one circuit produced by conduction from the other, and control means for each compartment.

Another object of the invention is the provision in a refrigerating system of separate primary and secondary refrigerating compartments with gravity circulation of the air in the colder compartment and forced circulation of air, when needed, in the compartment of higher temperature, and the primary refrigerant circulating through the cooler compartment and cooling a secondary refrigerant for the other compartment.

Other objects and advantages of the invention will be apparent from the following detailed description, and from the accompanying drawings showing two embodiments thereof in which- Fig. l is a vertical cross-section of a refrigerating unit embodying the invention taken on the line in Fig. 2 and looking toward the rear of the case; Fig. 2 is a vertical section from front to rear taken on the line 2-2 in Fig. 1; Fig. 3 is a fragmentary section on the line 3-3 in Fig. 2; Fig. 4 is a cross-section on the line 4-4 in Fig. 3; Fig. 5 is an enlarged fragmentary section on the line 55 in Fig. 4; Fig. 6 is an enlarged fragmentary section on the line 6-6 in Fig. 1, and Fig. 'I is a section similar to Fig. 2 with a different form of air circulating flue in the cold chamber.

Referring to the drawings, I designates a refrigerator case or cabinet having what may be termed a cold chamber 2 to which access is had through a door 3, and also having interiorly thereof, in the present instance, and in its upper portion, a freezing chamber 4 controlled by a door 5. The chambers 2 and 4 are heat insulated one from the other and the doors for both chambers fit closely to seal the chambers when the respective doors are closed.

The freezing chamber 4, in the present in stance, is smaller than the cold chamber 2, and is provided with two vertically spaced superimposed shelves 5 and I supported within a liner member 8 that is spaced from the side and bottom walls of the chamber. This liner, in its present embodiment, is of U-form with its legs attached at their free ends to and suspended from the top wall of the chamber in parallel spaced relation to the side walls and with its cross or loop portion in spaced relation to the chamber bottom for air circulation purposes. The liner is slightly spaced at the back from the rear end wall of the chamber to provide a space 9 therebetween, and its front end is preferably spaced from the front wall of the chamber.

The shelves 6 and 1 are built up to form freezer plates of the eutectic type and are of hollow watertight construction to form a shallow chamber i0 (Fig. 5) substantially throughout the area of the plates in which an eutectic solution is disposed in surrounding relation to portions of the refrigerant circulating coils, as hereinafter described, The bottom or loop portion of the lining 8 may form the top wall of the lower plate chamber I0, while a sheet l2 attached thereto may form its bottom wall.

The refrigerating means includes a primary system or unit for supplying freezing temperature to the freezing" chamber 4, and a secondary system or unit for supplying the desired temperature, less than freezing, to the cold chamber 2, the latter action being the result of direct conduction from the refrigerant circulating tubes of the primary unit to those of the secondary unit.

The primary unit comprises a gas compressor l5 driven by an electric motor I6, an outlet or dispensing tube I! from the compressor to a length of tubing 18 of rapid thermal conductive material, in the present instance, in the upper portion of the cold chamber 2. From the part Hi this tubing extends up into the freezing chamber where it passes backward and forward through the eutectic solution in the lower plate 6, as shown at I 9, and thence up and through the eutectic solution in the top plate 1 in the same manner, as shown at 20. The connection 2| between the lower and upper plate coils includes an inverted U loop 22 (Fig. 3) above the level of the top plate to prevent the liquid refrigerant from draining back from the upper plate to the lower plate. The tubing, after traversing the upper plate, connects with a- 3 larger accumulator tube section 23 extending crosswise of the chamber 4 through therear space 9, such section being inclined slightly upward from a horizontal and connected at its opposite end through an upward loop 24 and down tube section 25 to the inlet side of the compressor l5, thus completing the primary refrigerating circuit.

The sensitive element'of a thermostatic control for the refrigerating machine is disposed at 25 within the freezing chamber 4, being clamped to the connection 2| between the upper and lower plate coils l3 and 20, and the responsive control, in the present instance, is located at 21 within the upper part of the cold chamber 2. This control is in series through wires 28 with the motor circuit wires 29, so that an opening of the control circuit will stop the motor, as well understood in the art. Because the machine control is clamped to the connecting tube 2| between the freezer plates 6 and I, it is very responsive to the changing load conditions in both compartments of the refrigerator as reflected by the primary refrigerant.

The secondary refrigerating means for the cold chamber 2 comprises a coil 30 located in apassage 3| formed between the rear wall of said chamber and a partition 32, and open at top and bottom to the chamber. The coil 30 is preferably of the finned type and has an upper length 33 paralleling and closely clamped to the length l8 of the primary refrigerating line by members 34. This tube part 33 is of suitable rapid thermal conductive material so that refrigerant liquid in the coil 30 will be chilled by conduction from the refrigerant in the primary freezing line. The upper end f the passage 3| is enlarged, as shown at 35, and provided with an opening 36 to the chamber 2. A fan 31, driven by a motor 38, is disposed adjacent to this opening to create a down draft through said passage, and thus set up a circulation through the chamber. A thermostatic control for the fan motor is located at 33 and is responsive to temperature changes in the chamber 2, as well understood in the art. It will be noted that the entire secondary coil is located in convenient accessible position within the main compartment of the "cold chamber of the refrigerator, and is thus easily accessible for servicing.

A refrigerant gas is used in the secondary coil 30 and this rises from the lower loops of the coil refrigerant. Thus the thermostatic control in compartment 4 provides for circulating the primary refrigerant to the degee necessary to maintain a nearly constant temperature in compart- In Fig. 7 the enlarged space for the fan and its motor is shown as extended forward in gradually diminishing depth under the bottom wall of the freezing compartment, and with the partition j 40 which forms the same provided with a plurality of cross wise extending louvered slots ll While the preferred construction provides the two compartments in one insulated cabinet, with a partition with relatively little insulation between the compartments, in its broader aspects the invention would apply where the two compartments had separate insulated walls with a properly insulated conduit for the primary refrigerant from compartment 2 to compartment 4.

The present invention admirably adapts itself for use in connection with either domestic or commercial sized refrigerators and to the use of a small or large "freezing chamber therein. Also the "freezing chamber may be the same width as the main chamber with the side and top insulated walls formed by the respective walls of parting from the spirit of the claims.

Having thus described our invention, what we claim as new and desire to secure by United States Letters Patent is:

1. In a two-temperature refrigerator, two compartments, refrigerating means having a primary and liquefies when it comes in contact with the cold portion 33 thereof. then runs down through the pipe portion 30' by gravity and volatilizes on its way up through the loops as it picks up heat from the chamber 2, thus causing a continuous circulation through the secondary coil. The circulation of the air over the loops 3!) between plate 32 and the wall of the chamber is restricted'as desired to prevent over cooling of the "cold chamber under normal operating conditions.

The provision of the eutectic plates in the freezing chamber is important-in stabilizing the temperatures therein, first, when ice trays filled with water are placed in the freezer, as the v tures more nearly uniform while the bulk of refrigerating work is being done on the incoming line in the transference of cold to the secondary The liquid refrigerant refrigerant line with a coil in one of the compartments, a separate closed line for a refrigerant having a coil in the other compartment, the two lines being in heat-exchanging relation for a portion of their lengths, thermostatic means controlling circulation through said primary coil in accordance with the temperature in the first said chamber, a fan for circulating air in the said other compartment over the refrigerant coil therein, and thermostatic means governing the fan in accordance with the temperature in the said other compartment.

2. In a refrigerator, an insulated compartment, a closed refrigerant line in the compartment comprising a down line, a rising coil and a connecting pipe between the tops of the coil and the down line, a pipe for a refrigerant of approximately constant temperature in heat-exchange relation to the connecting pipe, a fan for forcing air down past the coil, and thermostatic means controlling the fan in accordance with the temperature in the upper portion of the compartment.

3. In a refrigerator, a freezing chamber and a cold chamber, one or more hollow plates in the freezing chamber serving as shelves and containing an eutectic solution, a primary refrigerating means with its refrigerant circulating line extending through each of said plates to chill the 76 eutectic solution therein, a secondary refrigerataaeaeaa ing means comprising a closed coil in said cold chamber with a portion in thermal conductive contact with said primary line in advance of said plates to chill and set up circulation of the secondary refrigerant in its line, and a thermostatic control for said primary line with its temperature-sensitive element in heat-conductive relation to the primary line between two of said plates.

4. In a refrigerator, a freezing chamber, a plurality of hollow vertically spaced plates in said chamber containing an eutectic solution, a refrigerating means including a refrigerant circulating line with successive portions in the solution in successive plates, connection between said portions with an inverted U bend entering the uppermost portion, an accumulator adjacent to and at the outlet side of said uppermost plate, and a thermostatic control for refrigerating means with its'heat-sensitive element in thermal relation to the refrigerant line between two of said plates.

5. In a two-temperature refrigerator, a freezing compartment, a cool compartment, a partition in the cool compartment forming a restricted verical channel, a refrigerating means comprising a line for a primary refrigerant having a coil in the freezing compartment, a closed line for a secondary refrigerant having a coil in said channel, a portion at the top of the second said line being in heat-exchange relation to the first said line, a fan for blowing air down through said channel, and thermostatic means controlling the fan in accordance with the temperature in the cooling compartment.

6. Apparatus in accordance with claim 5 and comprising thermostatic means for controlling circulation in said primary line in accordance with the temperature of said line at an intermediate point in the coil in the freezing chamber.

MINOR HARRISON STRANG. RALPH J. BURGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,261,682 Hedlund Nov. 4, 1941 2,261,683 Kuenzli 'Nov. 4, 1941 2,346,837 Grooms Apr. 18, 1944 2,350,249 Osburn May 30, 1944 

